Fin Tubes Mfg. Co. Supplies `G` Base Fin Tube. Fin Tubes Mfg. Co. Is the manufacturer of finned tubes, and inside/ outside integral finned tubes. `G` Base Fin Tube has the fin strip which is wound into a machined groove and securely locked into place by back filling with base tube material. `G` Base Fin Tube ensures that maximum heat transfer is maintained at high tube metal temperatures. It operates in maximum temperature of 450 degree centigrade.